These teachings relate generally to fluorescent materials, and more particularly to the preparation and use of one or more fluorescent materials to illuminate at least the end of a tape, such that at least the end may be visually observed and detected.
Recently, the trend in tapes has been to increase the tape's transparency. As tapes become increasingly clear, the ability to observe and detect the end and/or edge(s) of a roll of tape, i.e. where the tape falls back onto itself, when subsequently torn or cut has become significantly more difficult, especially in situations where an applicator or roll holder/cutter is not being used when tearing or cutting the tape.
A number of different approaches were exploited in an attempt to develop a tape in which the tape's end and/or edges could be easily located and detected, e.g. U.S. Pat. No. 3,537,578. This patent teaches the use of a continuous imprinted marking located along the length of the tape, preferably extending diagonally from one end to the other end of the tape, to indicate the free end of the tape. Once this tape is rolled, the free end of the tape is detected as a result of locating the break in the continuous imprinted marking located along the length of the tape. However, this approach relies heavily on the imprinted marking of the tape that detracts from the transparency characteristics of the tape.
U.S. Pat. No. 7,517,585 describes the use of encapsulated chromogenic materials that are incorporated on the support material of the tape to indicate the end of the tape. According to this teaching, upon separation of a desired length of the tape, the capsules or microcapsules containing the chromogenic material(s) are ruptured providing a visible color at the end of the tape, i.e. the tear site. However, the incorporation of the chromogenic materials, that is, the capsules or microcapsules, which is vital to producing the visibility of the end of the tape, substantially reduces the transparency of the tape.
In the past, there have been attempts in utilizing fluorescent materials within the tape to detect the tape's end, e.g., U.S. Pat. Nos. 6,767,628 and 7,252,880. However, even though, the technology described in these patents employ the use of fluorescent materials, such technology disadvantageously incorporates the fluorescent materials into the base layer of the tape. As tapes are constructed on many different thicknesses of base layer(s), dependent on the tape's use, these patent teachings would require the making and inventorying of numerous types of base layer(s) with varying thicknesses and colors. Furthermore, applicable base layer(s) for such technology would not be of standard production as opposed to a clear base layer, and would evidently require additional time and cost during manufacturing.
Given the recent trend toward increasing the transparency of a tape, as well as the limitations of existing methods of detecting the end and/or edge(s) of tape, there is a need for an end indicating tape that does not substantially take away from the transparency characteristics of the tape. There is a further need for an end indicating tape that requires fewer restrictions in its construction, such that many different colors and thicknesses of the tape may be produced without incurring additional time and cost, as with the current prior art.